I have another question of etiquette that I'd appreciate opinions on before later tonight when we play our second session.

If you have a player who hoses the competition and beats them outright and the opponent decides to give and lose the fight, do you let your player roll in any X's in an attempt to generate extra successes for future fights?

It felt kind of cheesy to allow players who had already clearly won to roll in X's in order to try and generate extra ones.